This application claims the benefit of the Korean Application No. P2001-44557 filed on Jul. 24, 2001, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a flat cathode ray tube (CRT), and more particularly, to a flat CRT panel, which can reduce weight and breakage during heat treatment.
2. Background of the Related Art
Referring to FIG. 1, a structure of a related art color CRT will be explained.
There is a funnel 2 fitted to rear of a panel 1. There is a fluorescent film coated on an inside surface of the panel 1, and there is an electron gun 8 sealed inside of the funnel 2 for emitting an electron beam 11 that makes the fluorescent film on the panel 1 luminescent. There are a deflection yoke 9 and a magnet 10 for deflecting the electron beam 11 to a required path. There are stud pins 6 fitted to the inside of the panel 1 for fastening a main frame 5, to which springs 4 of a shadow mask 3 and an inner shield 7 are fitted.
The operation of the related art color CRT will be explained.
Upon application of a voltage to the electron gun 8, the electron gun 8 emits the electron beam 11. The electron beam 11 emitted thus is deflected in left or right, or up or down direction by the deflection yoke 9, and hits the fluorescent film on inside of the panel 1, according to which a picture is reproduced.
In the meantime, since an inside of the CRT is under substantial high vacuum, such that the panel 1 and the funnel 2 are under a high tension or compression, to be susceptible to implosion caused by an external impact. Consequently, in order to prevent the implosion, the panel 1 is designed to have a certain structural strength, and furthermore, there is a reinforcing band 12 strapped around an outer circumference of skirt of the panel 1, for distribution of stresses on the CRT, thereby securing an impact resistance capability.
In the meantime, referring to FIG. 2A, most of the related art panels are non-flat panels. That is, both an inside surface and an outside surface of the panel have certain curvatures. However, it is current trend that the CRT becomes larger and flat. That is, referring to FIG. 2B, currently a flat panel 1 having almost no curvature on the outside surface is used, mostly.
Though the flat panel 1 has various advantages over the non-flat panel 1a, the flat panel 1 has a disadvantage in view of strength. Problems of the related art flat CRT panel will be explained.
First, referring to FIG. 3, the flat panel 1 has a distance from a mold match line to a seal edge line OMH greater than a non-flat panel 1a. That is, the flat panel 1 has an overall thickness greater than the non-flat panel 1, to cause breakage due to a high stress exceeding a critical stress coming from a difference of heat conduction during heat treatment of the panel. That is, basically, the flat panel 1 has a structure with a limitation from breakage.
Second, the flat panel 1 is comparatively thick, and heavy, to cost high and require components, such as frame and the like, to be large.
Accordingly, the present invention is directed to a flat CRT panel that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a flat CRT panel which can reduce panel breakage during heat treatment (Stabi, Frit Sealing, Evacuation).
Another object of the present invention is to provide a flat CRT panel which can reduce a panel weight and cost.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the flat CRT panel includes a substantially flat outside surface, and an inside surface of a fixed curvature, wherein the inside surface of the panel is formed to meet a condition of {(Rh+Rv)/2}xc3x97Rd=8.0-10.3, where xe2x80x9cRdxe2x80x9d denotes a representative diagonal sectional radius of curvature, xe2x80x9cRhxe2x80x9d denotes a representative long-axis sectional radius of curvature, and xe2x80x9cRvxe2x80x9d represents a representative short-axis sectional radius of curvature when an effective screen size of the panel is greater than 25xe2x80x3.
The panel preferably has a center part thickness greater than or equal to 12.0 mm, and more preferably in a range of 12.0-14.0 mm.
The panel preferably meets a condition of CFTxc3x97OAH of being in a range of 1297.10-1454.10, where CFT represents a panel center thickness, and OAH represents a distance from an outside surface of the panel to a seal edge of the skirt, and more preferably in a range of 1338.34-1411.84.
In another aspect of the present invention, there is provided a flat CRT panel including a substantially flat outside surface, and an inside surface of a fixed curvature, wherein a center part thickness of the panel is in a range of 11.9-13.1 if the inside surface of the panel meets a condition of Rh/Rd being in a range of 1.4-1.6, and Rv/Rd being in a range of 0.7-0.8, where xe2x80x9cRdxe2x80x9d denotes a representative diagonal sectional radius of curvature, xe2x80x9cRhxe2x80x9d denotes a representative long-axis sectional radius of curvature, and xe2x80x9cRvxe2x80x9d represents a representative short-axis sectional radius of curvature when an effective screen size of the panel is greater than 29xe2x80x3.
The center part thickness of the panel is preferably in a range of 12.1-12.7.
Thus, the flat CRT panel of the present invention can minimize panel breakage in heat treatment, and save a production cost.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.